Exceptional flame-retardant, super strong/tough, and superhydrophobic/self-cleaning wood

This study presents a novel approach to fabricate wood composites with exceptional flame retardancy, superior strength and toughness, as well as superhydrophobic/self-cleaning properties. The fabrication process involves densifying delignified wood pre-impregnated with a nitrogen-phosphorus flame retardant via hot-pressing, followed by an adhesive-free, self-curing superhydrophobic dip-coating. The resulting wood exhibits remarkable synergistic performance: exceptional flame retardancy, with peak heat release rate (pHRR) and total heat release (THR) decreased by 77.7 % and 63.6 %, respectively, compared with pristine wood; superhydrophobicity/self-cleaning with a water contact angle (WCA) of 161.2° and sliding rolling off angle (SA) of 3.9°; and outstanding mechanical performance with a tensile strength of 439 MPa and fracture toughness of 8.7 MJ/m 3 . Notably, this innovation addresses two critical challenges in fire-retardant wood technology—preventing flame retardant leaching and eliminating flammable adhesives—thereby offering a scalable method for the commercial production of high-performance wood composites suitable for applications in green architecture, transportation, and safety–critical infrastructure.